The Collaborative International Dictionary of English v.0.48:

Responsibility \Re*spon`si*bil"i*ty\ (r?*sp?n`s?*b?l"?*t?), n.;
   pl. -ties (-t?z). [Cf. F. responsabilit['e].]
   1. The state of being responsible, accountable, or
      answerable, as for a trust, debt, or obligation.
      [1913 Webster]

   2. That for which anyone is responsible or accountable; as,
      the resonsibilities of power.
      [1913 Webster]

   3. Ability to answer in payment; means of paying.
      [1913 Webster]

WordNet (r) 3.0 (2006):

responsibility
    n 1: the social force that binds you to the courses of action
         demanded by that force; "we must instill a sense of duty in
         our children"; "every right implies a responsibility; every
         opportunity, an obligation; every possession, a duty"- John
         D.Rockefeller Jr [syn: duty, responsibility,
         obligation]
    2: the proper sphere or extent of your activities; "it was his
       province to take care of himself" [syn: province,
       responsibility]
    3: a form of trustworthiness; the trait of being answerable to
       someone for something or being responsible for one's conduct;
       "he holds a position of great responsibility" [syn:
       responsibility, responsibleness] [ant:
       irresponsibility, irresponsibleness]

Moby Thesaurus II by Grady Ward, 1.0:

131 Moby Thesaurus words for "responsibility":
   accountability, accountableness, accounting for, action, agency,
   agentship, amenability, answerability, answerableness, application,
   arrogation, ascription, assignation, assignment, attachment,
   attribution, auspices, authority, authorization, blame, bossing,
   brevet, burden, care, charge, chargeability, commission,
   commissioning, commitment, conduct, connection with, consignment,
   credit, culpability, cure, dedication to duty, delegated authority,
   delegation, dependability, deputation, derivation from, devolution,
   devolvement, devotion to duty, direction, driving, duteousness,
   dutifulness, duty, embassy, empowerment, entrusting, entrustment,
   errand, etiology, execution, executorship, exequatur, exercise,
   eye, factorship, faithworthiness, fault, full power, functioning,
   guilt, handling, honor, imputation, incorruptibility, incumbency,
   intendance, inviolability, job, jurisdiction, legation, liability,
   license, lieutenancy, management, mandate, manipulation, mission,
   obligation, occupation, office, onus, operancy, operation,
   oversight, palaetiology, performance, performing, placement,
   plenipotentiary power, power of attorney, power to act, practice,
   procuration, proxy, purview, reference to, regency, regentship,
   reliability, responsibleness, role, running, saddling,
   sense of duty, sense of obligation, stability, steering,
   superintendence, supervision, sureness, surveillance, task, trust,
   trustability, trusteeship, trustiness, trustworthiness,
   unfalseness, unperfidiousness, untreacherousness,
   vicarious authority, warrant, work, working, workings



Bouvier's Law Dictionary, Revised 6th Ed (1856):

RESPONSIBILITY. The obligation to answer for an act done, and to repair any
injury it may have caused.
     2. This obligation arises without any contract, either on the part of
the party bound to repair the injury, or of the party injured. The law gives
to the person who has suffered loss, a compensation in damages.
     3. it is a general rule that no one is answerable for the acts of
another unless he has, by some act of his own, concurred in them. But when
he has sanctioned those acts, either explicitly or by implication, he is
responsible. An innkeeper in general, civilly liable for the acts of his
servants towards his guests, for anything done in their capacity of
servants. The owner of a carriage is also, civilly responsible to a
passenger for any injury done by the driver as such. See Driver.
     4. There are cases where persons are made civilly responsible for the
acts of others by particular laws and statutory provisions, when they have
not done anything by which they might be considered as participating in such
acts. The responsibility which the hundred (q.v.) in England formerly
incurred to make good any robbery committed within its precincts, may be
mentioned as an instance. A somewhat similar liability is incurred now in
some places in this country by a county, when property has been destroyed by
a mob.
     5. Penal responsibility is always personal, and no one can be punished
for the commission of a crime but the person who has committed it or his
accomplice. Vide Damages; Injury; Loss.



The Devil's Dictionary (1881-1906):

RESPONSIBILITY, n.  A detachable burden easily shifted to the
shoulders of God, Fate, Fortune, Luck or one's neighbor.  In the days
of astrology it was customary to unload it upon a star.

    Alas, things ain't what we should see
    If Eve had let that apple be;
    And many a feller which had ought
    To set with monarchses of thought,
    Or play some rosy little game
    With battle-chaps on fields of fame,
    Is downed by his unlucky star
    And hollers:  "Peanuts! -- here you are!"
                                                   "The Sturdy Beggar"